Masanori Yamada

Development of RAF Quality 150mm 4H-SiC Wafer

We have developed RAF (Repeated a-face) growth method which is high quality bulk crystal growth technology [1, 2]. A block crystal more than 150 mm square size was produced by the RAF growth method. Since c-face growth crystal was produced on the seed obtained from the block crystal, high quality 150mm 4H-SiC wafer was achieved. This paper reports the results of the quality evaluation.

Characterization of Vacant Broken Line Defects in A-Face Grown Crystals of Silicon Carbide

A new type of defects, vacant broken line defects, was found to occur in a-face grown crystals of 4H-Silicon Carbide. We characterized the vacant broken line defects by high voltage transmission electron microscope (HV-TEM). The HV-TEM image revealed that the edges of broken line defects were connected by a bundle of dislocations, which elongated to the growth direction on the basal plane. The analysis by gb method for determining Burgers vector indicated that the dislocations were not pure screw dislocations, but complex of screw and edge dislocations. The vacant broken line defect was considered to be a quasi-stable state of a bundle of basal plane dislocations in a-face growth, similar to a micropipe defect in c-face growth.